Exhaust Gas-Discharging Device of Vehicle

ABSTRACT

An exhaust gas discharge device for vehicles is disclosed. The exhaust gas discharge device of the present invention includes an extension pipe ( 10 ), which is fitted over a tail pipe of a silencer of a vehicle. A venturi passage ( 20 ) is defined in an exhaust gas inlet end of the extension pipe to increase a flow speed of the exhaust gas. The exhaust gas discharge device further includes an outside air discharge nozzle ( 30 ), which extends into the venturi passage, a backflow inlet port ( 40 ), which is provided in an exhaust gas outlet end of the extension pipe to guide outside air, and a cover ( 50 ), which defines therein a chamber, through which the backflow inlet port communicates with the outside air discharge nozzle. Thus, the present invention restrains backflow of exhaust gas using the flow of outside air, thus preventing back pressure, and rapidly discharging the exhaust gas, thereby enhancing the output of the engine.

TECHNICAL FIELD

The present invention relates, in general, to exhaust gas dischargedevices for discharging exhaust gas, used in internal-combustion enginesfor vehicles, and more particularly, to an exhaust gas discharge devicefor vehicles which is coupled to a tail pipe of a silencer provided inan exhaust gas discharge path of a vehicle and is constructed such thatthe backflow of exhaust gas is restrained by the flow of air, thuspreventing back pressure, and rapidly discharging the exhaust gas,thereby reducing fuel consumption and enhancing the output of theengine.

BACKGROUND ART

As well known to those skilled in the art, in an internal-combustionengine of a vehicle, power is obtained through a four-stroke cycleincluding an intake stroke, a compression stroke, an explosion strokeand an exhaust stroke.

With regard to the flow of gas (intake air and discharge air) during thestrokes of the engine, in the intake process, gas is drawn into theengine after passing through an air cleaner and a throttle valve withlittle resistance.

However, in the exhaust process, because exhaust gas is dischargedoutside the vehicle via an exhaust manifold, a gas purification devicecomprising a catalyst, and a silencer, there is a relatively largeamount of resistance to the discharge air flow.

During the process in which gas is discharged from the cylinder of theengine to the tail pipe of the silencer, a valve overlap, in which anintake valve and an exhaust valve are momentarily opened at the sametime in the exhaust manifold, occurs in the four-stroke cycle of theengine. At this time, exhaust gas, which is being discharged, is drawnback into the cylinder, so that the exhaust manifold momentarily entersa vacuum state, thereby forming primary back pressure that interfereswith the discharge of exhaust gas.

Furthermore, in a three-dimensional catalytic device, which is a gaspurification device, the flow speed of exhaust gas is markedly reducedwhile it passes through the gas purification device, having a honeycombshape, thus creating secondary back pressure. In addition, when exhaustgas, which is drawn into the silencer, passes through multi-steppedpartition plates to absorb noise, tertiary back pressure is created.

In this gas discharge process, because exhaust gas is discharged at apressure of approximately 3 to 5 kg/cm² and at a temperature ofapproximately 600° C., the silencer is essential. Typically, thesilencer is designed to have a capacity that is fifteen to twenty timeslarger than the engine displacement. However, such a silencer has adisadvantage in that exhaust gas is not smoothly discharged from theengine due to air resistance, thus reducing the output of the engine by5% to 10%.

Therefore, it is to be appreciated that the output of the engine can beenhanced and fuel consumption can be reduced merely by smoothlydischarging exhaust gas.

To achieve the smooth discharge of exhaust gas, various conventionaltechniques were proposed.

As a representative example, an exhaust gas discharge device forvehicles using the flow of air was proposed in Korean Patent Laid-OpenPublication No. 2000-56951. This technique, using the flow of air, isconstructed such that the streamline-shaped body of the exhaust gasdischarge device is coupled to a tail pipe, so that when the vehicletravels, a low pressure region is formed around the exhaust gasdischarge device by the flow speed of air that passes along the surfaceof the streamline-shaped body, so that exhaust gas is sucked out by thelower pressure, thus promoting the discharge of exhaust gas.

However, this technique is disadvantageous in that the streamline-shapedbody has a relatively large and complex structure affecting theinstallation thereof, and, when the vehicle is stopped or travels at arelatively low speed, because rapid air flow cannot be induced, thenarrow discharge passage interferes somewhat with the discharge ofexhaust gas. Therefore, it is very difficult to use this technique inpractice.

Meanwhile, as another example of the conventional arts, in a tail pipeof a main silencer having a vortex generator, which was proposed inKorean Patent Laid-Open Publication No. 1998-75223, a vortex generatingblade is provided at a medial portion in the tail pipe so as to berotatable by exhaust gas. This technique is constructed such that theblade is rotated by exhaust gas, thus generating vortexes, therebypromoting the discharge of exhaust gas. However, there is a problem inthat the blade serves as a source of some resistance that interfereswith the flow of exhaust gas, and thus it cannot be used in practice.

As another example of conventional arts, in an exhaust gas dischargingdevice for vehicles, which was proposed in Korean Utility ModelRegistration No. 99434, an exhaust gas discharge device is coupled to atail pipe using locking bolts, and a plurality of vortex generatingblades is radially provided on the circumferential inner surface of thepipe. This exhaust gas discharging device was proposed to achieve animprovement in discharge efficiency. However, it is difficult to rapidlyand smoothly discharge exhaust gas using only vortexes generated in theexhaust gas. In other words, there is only a slight effect in whichvortexes of fluid partially assist the discharge of exhaust gas, whichis naturally discharged by exhaust pressure. As such, the efficiency ofthe device is very low.

Furthermore, as another example of the conventional arts, in an exhaustgas discharging device using vortexes, which was proposed in KoreanPatent Registration No. 257874, a vortex generating duct, which includesa vane that draws outside air and generates vortexes, is provided on thefront pipe of a silencer, which is provided in an exhaust gas dischargepath. The exhaust gas discharging device further includes a sub duct,which has therein a valve that adjusts the degree of opening thereof inproportion to the opening degree of a throttle valve.

However, in this technique, because the duct is provided on the frontpipe of the silencer, which serves to reduce exhaust noise, exhaustnoise is transferred outside through the duct. Moreover, when thevehicle accelerates, the degree of opening of the valve is increased,and thus exhaust noise becomes severe. Furthermore, because exhaust gasis discharged through the sub duct, which has low air resistancecompared to the interior of the silencer, outside air cannot be smoothlysupplied into the duct because of the resistance. Therefore, it is alsodifficult to use this technique in practice.

In addition, in this technique, because outside air is drawn into aninlet of the silencer, air resistance still occurs in the silencer, andthus it is not useful for increasing the exhaust rate. As well, thedevice is provided with an air regulating damper, which is operated inconjunction with the throttle valve of the engine, so that there is adisadvantage in that the structure thereof is complex. Because outsideair, drawn into the duct, passes through the silencer, foreignsubstances (dust, sand, etc.), which have been contained in the outsideair, are deposited in the silencer, thus deteriorating the performanceof the silencer.

In an effort to overcome the problems experienced with the conventionalarts, an exhaust gas discharge device for vehicles was proposed inKorean Patent Registration No. 464711, which was filed by the inventorof the present invention.

This technique is constructed such that, when a vehicle travels, outsideair is gathered using a flared tube, and is used to increase the exhaustpressure in a tail pipe, thus increasing the flow speed of exhaust gas.

That is, outside air is supplied into the flared tube to rapidlydischarge exhaust gas outside the exhaust pipe using a phenomenon inwhich the pressure of air is increased when the air flows through areduced area.

This technique realizes an increase in the flow speed of exhaust gas,thus having advantages of enhancing the output of the engine andreducing fuel consumption. However, there is a disadvantage in that,when the vehicle is stopped or travels at a low speed, the effect ofthis technique is markedly reduced.

Furthermore, a technique was proposed in Korean Patent Application No.2004-13721, which was filed by the inventor of the present invention,the technique relating to a structure such that two stationary vanes areformed in a tail pipe by cutting and bending portions of the sidewall ofthe tail pipe inwards, so that the discharge of exhaust gas is promoted,and outside air, which is drawn backwards when the engine is in thevalve overlap state, is discharged outside through the vane, thusincreasing the output of the engine. Furthermore, a circulation exhaustgas discharge device was proposed in Korean Utility Model RegistrationNo. 374553, which was filed by the inventor. In this circulation exhaustgas discharge device, first and second stationary vanes 1 and 2, each ofwhich has a streamlined shape, are formed in the tail pipe of a silencerof a vehicle by cutting and bending portions of the sidewall of the tailpipe inwards. The first and second stationary vanes are disposed atpositions spaced apart from each other by a predetermined distance, andface each other. In addition, the circulation exhaust gas dischargedevice includes a housing 3, which covers the first and secondstationary vanes such that the first and second stationary vanescommunicate with each other therethrough and are isolated from theatmosphere thereby. Thus, this exhaust gas discharge device promotes anincrease in the flow speed of exhaust gas at the discharge end of thesilencer. The inventor of the present invention proposed theabove-mentioned techniques and several other techniques, which pertainto the exhaust gas discharge device.

The present invention is provided to improve the functions of theconventional techniques proposed by the inventor.

DISCLOSURE [Technical Problem]

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and has the followingobjects.

An object of the present invention is to provide an exhaust gasdischarge device for vehicles, in which exhaust gas discharged through atail pipe of a silencer is increased in speed by a venturi phenomenon,and outside air drawn thereby is circulated and discharged, thusaccelerating the exhaust speed of exhaust gas, thereby making itpossible to discharge the exhaust gas more rapidly.

Another object of the present invention is to provide an exhaust gasdischarge device for vehicles which is constructed such that exhaust gascan be rapidly discharged, and in addition, some exhaust gas, whichflows backwards, can be discharged outside the tail pipe along withoutside air, which is circulated and discharged, thus preventing exhaustgas from being drawn back into an engine or forming back pressure,thereby increasing the output of the engine.

A further object of the present invention is to provide an exhaust gasdischarge device for vehicles which has a solid structure, thus markedlyincreasing the durability thereof, and can be applied to an existingvehicle without changing the construction of the existing silencer, thushaving superior intercompatibility.

Yet another object of the present invention is to provide an exhaust gasdischarge device for vehicles which markedly reduces the backflow ofexhaust gas, thus preventing combustion residue, such as carbon, frombeing deposited, thus extending the lifetime of the engine, andmaintaining the components of the exhaust system, including an expensivegas purification device, clear and in a normal state, thereby extendingthe lifetime of the components.

[Technical Solution]

In order to accomplish the above objects, the present invention providesan exhaust gas discharge device for a vehicle, comprising: an extensionpipe fitted over the tail pipe of a silencer of the vehicle, with aventuri passage defined in an exhaust gas inlet end of the extensionpipe to increase the flow speed of the exhaust gas; an outside airdischarge nozzle extending into the venturi passage; a backflow inletport provided in an exhaust gas outlet end of the extension pipe toguide the inflow of outside air; and a cover fitted over the extensionpipe to define therein a chamber, through which the backflow inlet portcommunicates with the outside air discharge nozzle, so that the flowspeed of exhaust gas is increased at the distal end of an exhaust gasdischarge path and the backflow of exhaust gas is prevented, thusenhancing the output of the engine.

[Advantageous Effects]

As described above, in the present invention, the exhaust gas dischargedevice is additionally coupled to the tail pipe of a silencer, throughwhich exhaust gas is discharged outside. Therefore, the presentinvention can be easily applied to an existing vehicle without changingthe construction of the existing exhaust system. Furthermore, exhaustgas is rapidly discharged by a venturi phenomenon, and outside air,which is drawn into a chamber of the exhaust gas discharge device and iscirculated and discharged outside the vehicle, prevents the backflow ofexhaust gas and thus prevents back pressure, thereby improving exhaustefficiency and enhancing the output of the engine. In addition, thepresent invention is designed such that the structures of the outsideair discharge nozzle and the backflow inlet port can be changed, so thatdesign of the chamber for forming a low pressure state therein can beeasily conducted. As well, the present invention has a solid structure,thus markedly increasing the durability thereof, and can be applied toan existing vehicle without changing the construction of the existingsilencer, thus having superior intercompatibility. Moreover, the presentinvention markedly reduces the backflow of exhaust gas, thus preventingcombustion residue, such as carbon, from being deposited, thus extendingthe lifetime of the engine, and maintaining components of the exhaustsystem, including an expensive gas purification device, clear and in anormal state, thereby extending the lifetime of the components.

Meanwhile, although the exhaust gas discharge device of the presentinvention is illustrated as being used in vehicles, it will be easilyappreciated that the present invention can be applied to any mechanismusing an internal-combustion engine provided with a silencer having atail pipe.

DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing a conventional exhaust gas dischargedevice for vehicles, a patent application for which was filed by theinventor of the present invention;

FIG. 2 is a sectional view showing the construction of an embodiment ofthe present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is a right side view of FIG. 2;

FIG. 5 is a sectional view showing the construction of anotherembodiment of the present invention;

FIG. 6 is a view illustrating the installation of the present invention;

FIG. 7 is a view showing the operation of the embodiment of FIG. 2 toillustrate the exhaust stream;

FIG. 8 is a view showing the operation of the embodiment of FIG. 5 toillustrate the exhaust stream; and

FIG. 9 is a sectional view showing the construction of a furtherembodiment of the present invention.

BEST MODE

Hereinafter, the present invention will be described in detail withreference to the attached drawings.

A preferred embodiment of the present invention is shown in FIGS. 2through 4.

The exhaust gas discharge device 100 of the present invention includesan extension pipe 10, which is fitted over a tail pipe that is providedon the end of a silencer of a vehicle. A venturi passage 20, which has arelatively small diameter to thus increase the flow speed of exhaustgas, is defined in an exhaust gas inlet end of the extension pipe.Outside air discharge nozzles 30 extend from a surface, defining theventuri passage 20, towards the center of the venturi passage. Backflowinlet ports 40, through which outside air is drawn, are formed in anexhaust gas outlet end of the extension pipe. The circulation exhaustgas discharge device 100 further includes a cover 50, which is fittedover the extension pipe to define therein a chamber 52, through whichthe backflow inlet port 40 communicates with the outside air dischargenozzle 30.

Meanwhile, as shown in FIG. 5, the present invention may further includea subsidiary venturi passage tube 22, which is provided in the venturipassage 20, and the opposite ends of which are increased in diameter.Furthermore, the present invention may be constructed such that theoutside air discharge nozzles 30 extend predetermined lengths into thesubsidiary venturi passage tube 22, so that the ends of the nozzlescommunicate with the subsidiary venturi passage tube 22, and thesubsidiary venturi passage tube 22 is supported by the nozzles 30 at thecenter of the venturi passage 20.

The outside air discharge nozzles 30, which extend from the extensionpipe 10 into the venturi passage 20, are inclined in the direction inwhich exhaust gas is discharged. Each nozzle comprises an inclined pipe,the diameter of which is reduced from the chamber 52 to its dischargeend, through which air is discharged.

Preferably, the number of outside air discharge nozzles 30 may beselected from among two through four outside air discharge nozzles 30(refer to FIG. 3).

The backflow inlet ports 40, through which outside air is drawn, areprovided in the exhaust gas outlet end of the extension pipe 10, andeach comprise a pipe having a predetermined length. Preferably, thenumber of backflow inlet ports 40 may be selected among from two throughfour backflow inlet ports 40 (refer to FIG. 4).

In the drawings, the reference numeral 16 denotes slits, through whichthe extension pipe is coupled to the tail pipe of the silencer.

The operation of the present invention, having the above-mentionedconstruction, will be explained in detail herein below.

As shown in FIG. 6, the exhaust gas discharge device 100 of the presentinvention is fitted over and fastened to the circumferential outersurface of the tail pipe of the typical silencer 60 using a clamp or thelike. As such, the installation of the present invention can be easilyconducted.

Typically, after exhaust gas, which is generated by the operation of anengine through a typical process, is drawn into the silencer 60, noiseis reduced in an expansion chamber of the silencer 60 and, thereafter,the exhaust gas is discharged outside the silencer.

As shown in FIG. 7, exhaust gas, which has been discharged from thesilencer, is drawn into the extension pipe 10 of the exhaust gasdischarge device 100 of the present invention. The exhaust gasthereafter passes through the venturi passage 20, the diameter of whichis reduced, at an increased velocity, thus increasing the exhaustionvelocity thereof, and simultaneously drawing air, which is in thechamber 52, through the outside air discharge nozzles 30, which extendinto the venturi passage 20. Thus, the air is discharged along with theexhaust gas, so that the chamber enters a momentary low pressure state.After the exhaust gas is discharged, backflowing stream of thedischarged exhaust gas is drawn into the chamber, which is in the lowpressure state, through the backflow inlet ports 40.

Thus, the backflowing exhaust gas stream is not moved towards the engineand is again discharged outside through the chamber 52 of the exhaustgas discharge device. Here, this process, by which exhaust gas is guidedto the venturi passage and discharged outside at a relatively highspeed, is repeatedly conducted.

Therefore, exhaust gas, which is discharged along with negative pressurewaves, serves to eliminate back pressure because negative pressure wavesof the backflow are removed by the exhaust gas discharge device.

Here, in the operation of the engine, in which several tens or onehundred and several tens of intake processes and exhaust processes arerepeated per second, several tens or one hundred and several tens ofprocesses of discharging exhaust gas and processes of stopping thedischarge of exhaust gas are also repeated. At this time, the exhaustsystem alternately and repeatedly enters a positive pressure state and anegative pressure state. In addition, when the exhaust system enters thenegative pressure state while exhaust gas having exhaust inertia isdischarged, the backward inflow of outside air is induced. In theconventional art, this outside air, which is drawn backwards, serves asback pressure, with the result that the output of the engine is reduced.However, in the present invention, in a state in which the discharge ofexhaust gas is momentarily stopped, at the moment that exhaust inertiais applied, low pressure is formed in the chamber 52, so that outsideair is drawn into the chamber 52 through the backflow inlet ports 40,which have low inflow resistance, thus removing back pressure, which isapplied to the exhaust system by the backflow in the conventional arts.

Therefore, in the pipe of the silencer, through which exhaust gas isdischarged, the discharge of exhaust gas is accelerated. Furthermore,when the engine is in the overlap state, because a backflowing exhaustgas stream is immediately re-discharged by the air circulation of theexhaust gas discharge device 100, including air intake and dischargingprocesses, discharge flow is prevented from being interfered with thebackflow, so that the discharge of exhaust gas can be smoothlyconducted. Thus, the output of the engine is increased, and fuelconsumption is reduced. As well, foreign substances, which remain in theexhaust system after combustion, can be smoothly removed, therebypreventing damage to components of the exhaust system, which areexpensive, and extending the lifetime thereof.

MODE FOR INVENTION

The present invention, having the above-mentioned construction andoperation may be modified, as shown in FIG. 5.

In detail, in the embodiment of FIG. 5, the air circulation operation,using a venturi passage 20 and a chamber 52, is the same as that of theprior embodiment. However, unlike the prior embodiment, the embodimentof FIG. 5 further includes a subsidiary venturi passage tube 22, whichis provided in the venturi passage 20, so that outside air, which haspassed through outside air discharge nozzles 30, is discharged throughthe subsidiary venturi passage tube 22. Thus, the discharge speed ofexhaust gas, which is increased through the venturi passage 20, isfurther increased by the subsidiary venturi passage tube 22 (see, FIG.8).

Each outside air discharge nozzle 30 comprises an inclined pipe, thediameter of which is reduced from the inlet end thereof, adjacent to thechamber 52, to the discharge end thereof, thus serving to increase theacceleration of discharged air. Furthermore, the outside air dischargenozzle 30 is inclined in the direction in which exhaust gas isexhausted, thus reducing resistance to the discharge flow of the exhaustgas.

Furthermore, backflow inlet ports 40 are disposed at the distal end ofthe exhaust gas discharge device to prevent outside air from being drawninto a gas discharge passage in an undesirable direction. The openingarea of each backflow inlet port 40 can be appropriately adjusted suchthat, when outside air is discharged through the outside air dischargenozzles 30, a momentary low pressure state is formed in the chamber 52.Furthermore, two through four, preferably two, backflow inlet ports 40are arranged in a circle at positions spaced apart from each other, asshown in the drawings.

The present invention, having the above-mentioned construction such thatthe discharge speed of exhaust gas is increased and back pressureapplied to the exhaust system is removed, may be modified for ease ofmanufacture, as shown in FIG. 9.

In detail, the extension pipe, through which exhaust gas is dischargedfrom the engine, is sectioned into a first pipe 12, which is disposedadjacent to the inlet of the extension pipe, and a second pipe 14, whichis disposed adjacent to the outlet of the extension pipe. The first pipe12 includes a bent part 12 a, which is formed by bending the end of thefirst pipe such that the diameter thereof is reduced to form a venturipassage, and a bent part 14 a is also formed in the end of the secondpipe 14. The first pipe 12 and the second pipe 14 are coupled to eachother through a cover 52, such that the bent parts 12 a and 14 a faceeach other, so that the bent parts 12 a and 14 a serve as both theventuri passage and a ring-shaped outside air discharge nozzle.

In this case, there is an advantage in that the outside air dischargenozzle can be easily provided in the venturi passage, and it is to beappreciated that the operation thereof is the same the basic embodimentof the present invention, described above.

Meanwhile, a connection plate 15, having a predetermined width, may becircumferentially welded to the circumferential outer surfaces of thefirst and second pipes 12 and 14, which are separated from each other,thus ensuring the structural strength of the extension pipe.

The structure of the exhaust gas discharge device, which includes theventuri structure such that the rapid discharge of exhaust gas isrealized by increasing the flow speed of exhaust gas of the engine, theoutside air discharge nozzle that extends into the venturi passage suchthat a low pressure state is formed in the chamber, and the backflowinlet port, can be variously modified, without departing from the scopeand spirit of the invention as disclosed in the accompanying claims.These modifications must be regarded as falling within the bounds of theclaims of the present invention.

1. An exhaust gas discharge device for a vehicle, coupled to a tail pipeof a silencer of the vehicle to improve a flow of exhaust gas, andcomprising: an extension pipe, with a venturi passage defined in anexhaust gas inlet end of the extension pipe to increase a flow speed ofthe exhaust gas; an outside air discharge nozzle extending into theventuri passage; a backflow inlet port provided in an exhaust gas outletend of the extension pipe to guide inflow of outside air; and a coverfitted over the extension pipe to define therein a chamber, throughwhich the backflow inlet port communicates with the outside airdischarge nozzle.
 2. The exhaust gas discharge device for the vehicleaccording to claim 1, further comprising: a subsidiary venturi passagetube provided in the venturi passage, the subsidiary venturi passagebeing increased in diameter at opposite ends thereof, wherein theoutside air discharge nozzle extends a predetermined length into thesubsidiary venturi passage tube (22), so that an end of the nozzlecommunicates with the subsidiary venturi passage tube, and thesubsidiary venturi passage tube is supported by the outside airdischarge nozzle (30) at a center of the venturi passage.
 3. The exhaustgas discharge device for the vehicle according to claim 1, wherein theoutside air discharge nozzle, which extends from the extension pipe intothe venturi passage, is inclined in a direction in which the exhaust gasis discharged, and the outside air discharge nozzle comprises aninclined pipe, a diameter of which is reduced from the chamber to an airdischarge end thereof.
 4. The exhaust gas discharge device for thevehicle according to claim 1, wherein the outside air discharge nozzleand the backflow inlet port respectively comprise at least two outsideair discharge nozzles and at least two backflow inlet ports.
 5. Theexhaust gas discharge device for the vehicle according to claim 1,wherein the extension pipe is sectioned into a first pipe, which isdisposed adjacent to an inlet of the extension pipe, and a second pipe,which is disposed adjacent to an outlet of the extension pipe, whereinthe first pipe has a bent part, which is provided in an end of the firstpipe such that a diameter thereof is reduced to form the venturipassage, and the second pipe has a bent part in an end thereof, so thatthe first pipe and the second pipe are coupled to each other through thecover, such that the bent parts face each other, thus the bent parts,having the reduced diameters, serve as both the venturi passage and as aring-shaped outside air discharge nozzle.
 6. The exhaust gas dischargedevice for the vehicle according to claim 2, wherein the outside airdischarge nozzle, which extends from the extension pipe into the venturipassage, is inclined in a direction in which the exhaust gas isdischarged, and the outside air discharge nozzle comprises an inclinedpipe, a diameter of which is reduced from the chamber to an airdischarge end thereof.
 7. The exhaust gas discharge device for thevehicle according to claim 2, wherein the outside air discharge nozzleand the backflow inlet port respectively comprise at least two outsideair discharge nozzles and at least two backflow inlet ports.